DESIGN.md asks for metadata panels to slide up from the bottom under
768px. A BottomSheet component provides the trigger pill and the sheet
(backdrop blur, scroll lock, Escape to close) and ResponsivePanel swaps
between it and the existing desktop <aside>, so panel content is mounted
once either way.
Applied to the Library/Online/Similar detail asides and to long pool
descriptions. Upload needed nothing: its metadata editor is already a
full-screen modal that stacks cleanly on small screens.
